Refrigeration evaporator



Oct. 18, 1938. I. .c. SMITH REFRIGERATION EVAPORATOR .2 'SheecIs-Sheet 1 Filed May 15, 1937 Summer Lawrence CJmIf/l dttorncu Patented Oct. 18, 1938 REFRIGERATION EVAPORATOR Lawrence C. Smith, Kenmore, N. Y., assignor to Fedders Manufacturing Company, Inc., Buffalo, N. Y.

Application May 15, 1937, Serial No. 142,883

3 Claims.

' This invention relates to electric refrigeration, and it has particular reference to a new and improved evaporator adapted for service in a domestic refrigerator operating on the compressor-condenser-expander circuit.

More particularly, the invention contemplates an evaporator adapted to receive volatile liquid refrigerant containing quantities of lubricating oil, so constructed as to require a minimum of overhead clearance and space when placed in a domestic refrigerator, so that the box temperatures may be maintained at all points within desired ranges without undue reduction of the box capacity. The evaporator of the present invention also is designed to operate on the flooded principle, but with a smaller charge of refrigerating fluid than has heretofore been deemed necessary, without, however, sacrificing the area available for heat exchange purposes.

A preferred embodiment of the invention, achieving the foregoing objectives by means of a simple and inexpensive construction, will be described in the. following portions of, this specification, to be read in conjunction with the appended drawings, wherein: Y

Fig. 1 is a side elevation of the evaporator with portions of the suction header broken away to show the internal structure;

Fig. 2 is a front view thereof,;-'

Fig. 3 is an enlarged fragmentary section on the line 3-3 of Fig. 2;

Fig. 4 is a top view of the refrigerated shelf; and

- Fig. 5 is an enlarged fragmentary section on the line 5-'-5 of Fig. 1.

The evaporator includes cylindrical supply and suction headers l and H, of small and large diameters respectively, which 'are horizontally disposed and connected to the terminals l2 and I3 respectively of each of a plurality of depending tubular ducts H. The terminals l2 extend through holes l formed in the bottom of the header l0, and project upward toapproximately the center thereof (Fig. 5). in each feed terminal I 2 at a point located immediately within the header. The terminals I 3 project but a short distance within the header ll through holes I1. 7

An inlet fitting I8 is secured to the rear end of the header I 0, and it is suitably connected to a tube i9 leading to a condenser or equivalent refrigerant supply source (not shown). A control device 20 of anykno'wn type is interposed in the supply tube 19 to control thenvolume of refrigerant supplied to the header Ill. The suc- A hole I6 is drilled tion header II is capped at its rear extremity by a fitting 2| which communicates with a suction .tube 22 through which the gaseous products of evaporation and returning oil are withdrawn from the evaporator. The front end of the header ll receives a head 23-. A perforated baille tube 25 is concentrically disposed within the header II and its extremities are supported onprojections 26, 21, formed on the fitting 2| and head 23 respectively; The tube 25 thus divides the header into innerand outer chambers 28 and 29; the outer chamber, being in direct communication with the terminals (3, receives the full force of the relatively violent periodic discharges of the ducts, which is expnded on the circular wall thereof. The communicating inner chamber 28 is thus fully protected, and the liquid therein remains in a trim quil state, subject only to variations in liquid level, as dictated by the rates of evaporation and supply. .A suction pipe 30 projects angularly from the fitting 2| and its open end is disposed at a high point in the inner chamber 23.

To prevent the displacement of liquid 'in the supply header I0 and adjoining portions of the ducts I4 by gas volumes, an equalizing tube 3| is positioned in one of the ducts H with its terminals projecting to high points in both headers. Communication is thus established between the gas pockets at the top of the headers, and as a result pressures are equalized and the liquid in the evaporator is permitted to assume natural gravitational levels. If necessary, several of the ducts may be supplied with equalizing tubes.

In applying the inventionto domestic refrigerators, it is advantageous to form the ducts M of fairly large diameter tubing, and to flatten major portions transversely, as indicated by the numeral 32 (Fig. 3), so that larger areas of direct heat exchange surface are presented to the ambient air currents in the box in which the evaporator is mounted. Inasmuch as the flattening operation reduces the volumetric capacity of the ducts, it will be apparent that the benefits of the enlarged areas may be obtained with but a relatively small charge of refrigerant i'rlgerated types SI and 3!, respectively. The refrigerated she]! 38 has a loop 31 of flattened tubing soldered to its lower surface, with the terminals 38 and 39, which are not flattened, projecting outward and upward for communication with the headers III and II respectively, in a similar manner to the ductsl4. The sleeve 33 is formed with notches ll which receive the terminals 3! and 39 in assembly.

In operation, the liquid level in the evaporator is maintained by. the controls at a normal point below the center of the supply header ll. The liquid is introduced into the ducts ll through the small oriflces II in the feed terminals II, which insures that each duct is supplied with substantially equal volumes-oi refrigerant at a steady rate. Inasmuch as the levels'in the header II are reflected in the header ll, due to the pressure equalizing effects of the tube II, it will be observed that the headers are disposed so that even in extreme cases, where the level approaches the center of the inlet header (Fig. 5) the level is below the mouth of the suction pipe-ll in the header ll.

While the invention has been described in connection with a single embodiment, it will be understood that it is susceptible of numerous modiflcations and variations, and accordingly it should be construed as commensurate with the scope of the following claims.

I claim:

1. A refrigeration evaporator comprising a pair of spaced headers disposed horizontally at substantially the same level, an ice tray sleeve disposed beneath the headers, a plmality of ducts extending about the sides and bottom of the sleeve in thermal contact therewith, said ducts being flattened transversely of the sleeve, the

extremities of the ducts extending through the lower portions oi both headers, the extremities entering one header being each formed with a small oriflce adjacent the point of entry, a refrigerant supply conduit communicating with said last named header and a suction conduit communicating with the remaining conduit.

2. A refrigeration evaporator comprising horizontally disposed tubular suction and inlet headers, said inlet header being of a substantially smaller diameter than the suction header and being disposed at substantially the same level, a plurality 0! depending ducts having extremities extending through lower portions of both headers, the extremities entering the inlet header extending upward to substantially the diametrical plane oi the header, said extremities being each formed with .a small orifice adjacent the point oi. entry in the inlet header, a refrigerant supplyconduit communicating with the inlet header and a suction conduit communicating with the suction header.

3. A refrigeration evaporator comprising horizontally disposed tubular inlet and outlet headers, a plurality of depending ducts having extremities extending through lower portions of both headers, the extremities entering the inlet header extending upward to substantially the diametrical plane of the header, said extremities being each formed with a small orifice adjacent 

